The flaw, known as the "shell" exploit, was publicized Wednesday on a security mailing list, along with a link to a fix for the problem. Updated versions of the affected software programs, which include the Mozilla, Firefox and Thunderbird browsers, have been released.
Developers said the flaw affected only Windows users, not computers running either the Macintosh or Linux operating systems. Like recent Internet Explorer vulnerabilities, this flaw only allows the attacker the ability to run an existing program and requires that security problems in other applications be exploited to gain further access.